VCO spur radiation issue with Si4x6x RF chips

by <a href="http://community.silabs.com/t5/Welcome-and-Announcements/Community-Ranking-System-and-Recognition-Program/m-p/140490#U140490"><font color="#000000"><font size="2">Ninja Employee</font></font> </a> zovida on ‎08-07-2014 07:37 AM - edited on ‎08-13-2014 05:09 AM by Administrator Nari

Question

I see high radiated spur within the frequency range of the Si4x6x RF chip VCO signal. How can I suppress this?

Answer

In RX only boards due to the lack of additional filtering the VCO signal might be radiated via the antenna too. In that case some filtering between the antenna and the matching balun network is recommended.

Moreover, the filtering of the traces connected to the SDN, GPIO 2 and 3 pins is also suggested at the VCO frequency (not only in case of RX only boards).